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  • Optimal penalty stiffness values of concurrent 2D elastic interface elements leading to accurate stress tractions

     Ciancio, Daniela; Carol Vilarasau, Ignacio; Castellazzi, G.
    International journal for numerical methods in engineering
    Vol. 98, num. 5, p. 344-370
    DOI: 10.1002/nme.4633
    Date of publication: 2014-05
    Journal article

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    Zero-thickness interface elements are used to model contact surfaces or potential cracks. In these cases, their elastic stiffness is often set extremely high to reproduce a rigid behavior. This paper shows that the values of the stress tractions at the nodes of these elements can be affected by an error. A new procedure is proposed here, consisting of adding some nondimensional coefficients (purely geometry-dependent) to the values of the interface stiffness parameters. Thus doing, the accurate tractions at the interface nodes are recovered. Copyright (c) 2014 John Wiley & Sons, Ltd.

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    Hydro-mechanical coupling in zero-thickness interface elements, formulation and applications in geomechanics  Open access

     Garolera Vinent, Daniel; Aliguer Piferrer, Ignasi; Carol Vilarasau, Ignacio; Martínez Segura, J.M.; Lakshmikantha, Ramasesha Mookanahallipatna; Alvarellos Iglesias, José
    ISRM European Rock Mechanics Symposium
    p. 1379-1384
    DOI: 10.1201/b16955-240
    Presentation's date: 2014-05-26
    Presentation of work at congresses

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    Zero-thickness joint/interface elements of the Goodman type, have been advantageously used to solve many problems in solid mechanics involving material interfaces or discontinuities. Some years ago, the authors have also proposed a version of such element for flow/diffusion and hydro-mechanical (H-M) coupled problems, either geomechanical or multiphysics. Some advantages are for instance that fluid pressure discontinuities and localized flow lines may be represented on the same FE mesh used for the mechanical problem, as well as the influence of fluid pressure on mechanical stresses or, conversely, of crack openings on the flow redistribution ("cubic law"). In the paper, previous developments are briefly described, together with some new Geomechanical applications under development, particularly the application to the hydraulic fracture problems, which in the past have been studied mainly via analytical or semi-analytical formulations, or using mixed FE-FD approaches.

    Zero-thickness joint/interface elements of the Goodman type, have been advantageously used to solve many problems in solid mechanics involving material interfaces or discontinuities. Some years ago, the authors have also proposed a version of such element for flow/diffusion and hydro-mechanical (H-M) coupled problems, either geomechanical or multiphysics. Some advantages are for instance that fluid pressure discontinuities and localized flow lines may be represented on the same FE mesh used for the mechanical problem, as well as the influence of fluid pressure on mechanical stresses or, conversely, of crack openings on the flow redistribution (

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    Efficient numerical integration of Perzyna viscoplasticity, with application to rock slope stability using zero-thickness interface elements  Open access

     Aliguer Piferrer, Ignasi; Carol Vilarasau, Ignacio
    ISRM European Rock Mechanics Symposium
    p. 847-851
    DOI: 10.1201/b16955-145
    Presentation's date: 2014-05-26
    Presentation of work at congresses

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    In this paper, Perzyna-type viscoplastic rate equations are integrated for a time step by considering the step as stress-driven. Depending on how the increment is imposed (constant, linear etc.), different strategies arise. The secant compliance is obtained by truncated expansion of the yield function. The viscoplastic model can be applied to materials exhibiting rate-dependent behavior, but it can also be used to recover an inviscid elastoplasticity solution when stationary conditions are reached.Within this framework, a viscoplastic relaxation iterative strategy is developed, relating the iterations with the fictitious time steps. Some examples of application are presented in the context of the Finite Element Method with zero-thickness interface elements for slope and stability problems with discontinuities. © 2014 Taylor & Francis Group, London.

    In this paper, Perzyna-type viscoplastic rate equations are integrated for a time step by considering the step as stress-driven. Depending on how the increment is imposed (constant, linear etc.), different strategies arise. The secant compliance is obtained by truncated expansion of the yield function. The viscoplastic model can be applied to materials exhibiting rate-dependent behavior, but it can also be used to recover an inviscid elastoplasticity solution when stationary conditions are reached.Within this framework, a viscoplastic relaxation iterative strategy is developed, relating the iterations with the fictitious time steps. Some examples of application are presented in the context of the Finite Element Method with zero-thickness interface elements for slope and stability problems with discontinuities. © 2014 Taylor & Francis Group, London.

  • A method for the calculation of inter-element stresses in 3D

     Ciancio, Daniela; Carol Vilarasau, Ignacio; Cuomo, Massimo
    Computer methods in applied mechanics and engineering
    Vol. 254, p. 222-237
    DOI: 10.1016/j.cma.2012.11.014
    Date of publication: 2013-02
    Journal article

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  • 3D-mesomechanical analysis of cracking and spalling of concrete subject to high temperatures

     Pérez, A.; Rodriguez, Mariana; Lopez Garello, Carlos Maria; Carol Vilarasau, Ignacio
    International Conference on Computational Plasticity Fundamentals and Applications
    p. 1015-1025
    Presentation's date: 2013-09
    Presentation of work at congresses

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    In this paper, an existing meso-structural model for concrete which had been applied to the study of the mechanical effects of high temperatures in 2D, is extended to 3D, and to more complex coupled thermo-mechanical analysis. The material is idealized as a two-phase compositein which all mesh lines (or surfaces in 3D) are potential cracks equipped with fracture-based zero-thickness interface elements. Different thermal expansion laws are assumed for matrix and particles, whereby the deformation mismatch can generate cracking. Temperature distributions are obtained from a separate thermal diffusionanalysis.The thermal analysis is first assumed uncoupled, but then also coupled with the mechanical analysis, as the layers of material spalloff and the boundary conditionsare moved to the new domain boundaries. The new computational results in 3D are compared to basic experimental observations reported in the literature and to the previous computational results obtained in 2D.

  • On integration strategies for Perzyna-type viscoplasticity, and application to zero-thickness interface elements

     Aliguer Piferrer, Ignasi; Carol Vilarasau, Ignacio; Sture, Stein
    International Conference on Computational Plasticity Fundamentals and Applications
    p. 1331-1340
    Presentation's date: 2013-09
    Presentation of work at congresses

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    In this paper, Perzyna-type viscoplastic rate equations are integrated for a time step by considering the step as stress-driven. Depending on how the increment is imposed (constant, linear etc.), different strategies arise. The secant compliance is obtained by truncated expansion of the yield function. The viscoplastic model can be applied to materials exhibiting rate-dependent behavior, but it can also be used to recover an inviscid elastoplasticity solution when stationary conditions are reached. Within this framework, a viscoplastic relaxation iterative strategy is developed, relating the iterations with the fictitious time steps. Some examples of application are presented in the context of the Finite Element Method with zero-thickness interface elements for slope and stability problems with discontinuities.

  • Zero-thickness interface elements with H-M coupling, formulation and applications in geomechanics

     Garolera Vinent, Daniel; Aliguer Piferrer, Ignasi; Segura Segarra, José María; Carol Vilarasau, Ignacio; Lakshmikantha, Ramasesha Mookanahallipatna; Alvarellos Iglesias, José
    International Conference on Computational Plasticity Fundamentals and Applications
    p. 1372-1383
    Presentation's date: 2013-09-03
    Presentation of work at congresses

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    Previous developments on zero-thickness interface elements for coupled Hydro-Mechanics problems are briefly described, followed by some new geomechanical applications, particularly to hydraulic fracture in rock. The results are compared satisfactorily to approximate formulas and previously published numerical results. Once verified, the model is applied to new cases to show the capabilities of the approach.

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    Recent developments in durability mesomechanics of concrete, including cracking via interface elements  Open access

     Liaudat, Joaquin; Rodriguez, Mariana; Lopez Garello, Carlos Maria; Carol Vilarasau, Ignacio
    RILEM International Symposium on Creep and Shrinkage of Concrete
    p. 174-181
    DOI: 10.1061/9780784413111.020
    Presentation's date: 2013-10
    Presentation of work at congresses

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    The mesomechanical model for concrete, previously developed for purely mechanical actions, is used as the basis for coupled durability mechanics calculations. Until now, the phenomena studied include drying shrinkage, external sulfate attack and mechanical effects of high temperatures. On-going work is focusing on alkali-silica reaction (ASR). From the chemical viewpoint, ASR is represented with a three-field, diffusion-reaction, chemical model which is shown to qualitatively and quantitatively reproduce some experimental measurements of sandwich-type specimens subject to standardized accelerated ASR tests. The model developed includes the recently identified role of calcium in this type of expansive reactions.

    The mesomechanical model for concrete previously developed for purely mechanical actions, is used as the basis for coupled durability mechanics calculations. Until now, the phenomena studied include drying shrinkage, external sulfate attack and mechanical effects of high temperatures. On-going work is focusing on alkali-silica reaction (ASR). From the chemical viewpoint, ASR is represented with a three-field diffusion-reaction chemical model, which is shown to qualitatively and quantitatively reproduce some experimental measurements of sandwich-type specimens subject to standardized accelerated ASR tests. The model developed includes the recently identified role of Calcium in this type of expansive reactions.

  • Fictitious elastic stiffness parameters of zero-thickness interface elements to recover accurate nodal stresses

     Ciancio, Daniela; Carol Vilarasau, Ignacio; Castellazzi, G.
    International Conference on Computational Modeling of Fracture and Failure of Materials and Structures
    p. 74
    Presentation's date: 2013-06
    Presentation of work at congresses

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  • Meso-mechanical modelling of concrete, advances and applications to confined fracture

     Carol Vilarasau, Ignacio; Montenegro, Oscar Ivan; Lopez Garello, Carlos Maria
    International PREVI Workshop on Concrete Structures under Impact and Blast Loads
    p. 12
    Presentation's date: 2013-04
    Presentation of work at congresses

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  • Cracking of concrete under environmental processes using zero-thickness interface elements

     Carol Vilarasau, Ignacio
    International Conference on Computational Modeling of Fracture and Failure of Materials and Structures
    p. 62
    Presentation's date: 2013-06
    Presentation of work at congresses

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  • 3D numerical model of a confined fracture tests in concrete

     Montenegro, Oscar Ivan; Sfer, Domingo; Lopez Garello, Carlos Maria; Carol Vilarasau, Ignacio
    International Conference on Computational Plasticity Fundamentals and Applications
    p. 470-478
    Presentation's date: 2013-09
    Presentation of work at congresses

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    The paper deals with the numerical simulation of a confined fracture test in concrete. The test is part of the experimental work carried out at ETSECCPB-UPC in order to elucidate the existence of a second mode of fracture under shear and high compression, and evaluate the associated fracture energy. The specimen is a short cylinder with also cylindrical coaxial notches similar the one proposed by Luong (1990), which is introduced in a large-capacity triaxial cell, protected with membranes and subject to different levels of confining pressure prior to vertical loading. In the experiments, the main crack follows the pre-established cylindrical notch path, which is in itself a significant achievement. The load-displacement curves for various confining pressures also seem to follow the expected trend according to the underlying conceptual model. The FE model developed includes zero-thickness interface elements with fracture-based constitutive laws, which are pre-inserted along the cylindrical ligament and the potential radial crack plane. The results reproduce reasonably well the overall force-displacement curves of the test for various confinement levels, and make it possible to identify the fracture parameters including the fracture energies in modes I and IIa.

  • Diffusion-reaction model for Alkali-Silica Reaction in concrete

     Liaudat, Joaquin; Lopez Garello, Carlos Maria; Carol Vilarasau, Ignacio
    International Conference on Computational Plasticity Fundamentals and Applications
    p. 479-489
    Presentation's date: 2013-09
    Presentation of work at congresses

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    A new diffusion-reaction model for the potentially deleterious Alkali-Silica Reaction (ASR) process in concrete is presented. The model involves three coupled diffusion processes, two in-going and one out-going from the aggregate view point. Alkali (Na+and K2+)and Calcium (Ca2+)ions diffuse "inwards", from high molar concentration sites in the pores of the cement paste phase of the concrete specimen or at its boundaries,towards the aggregate-cement paste interfaces or the inner cracks of the aggregates. The OH-ions associated with alkali and calcium ions attack certain forms of silica in the aggregates (the "reactive silica"), dissolving it in the form of silicate ions which in turn diffuse back to the cement paste phase ("outwards"). The final potentially deleterious ASR precipitation process involves those silicate ions, plus calcium and alkalis. It takes place wherever the reactants are available by precipitating silicate hydrates of two kinds (Calcium-Silicate-Hydrates -CSH or Calcium-Alkali-Silicate-Hydrates -CASH) in a proportion depending on concentrations and temperature.The diffusion-reaction equations of this process are discretized in space and time using finite differences.An example of application in 1D is presented to illustrate the capabilities to reproduce realistically the ASR process, including some novel features not usuallywhich are not considered in the available literature, such as the role of calcium in the development of the reaction and the inherent relationship between the reaction product composition and its swelling capacity.

  • Durability meso-mechanics of concrete and mortar, with cracking via interface elements

     Carol Vilarasau, Ignacio; Liaudat, Joaquin; Lopez Garello, Carlos Maria
    Multi-Physics Modeling of Concrete and Heterogeneous Materials
    p. 37
    Presentation's date: 2013-10
    Presentation of work at congresses

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  • Multiscale modeling of mechanical and environmental degradation of heterogeneous materials using fracture-based interface elements

     Carol Vilarasau, Ignacio
    Asia Pacific Congress on Computational Mechanics & International Symposium on Computational Mechanics
    p. 1
    Presentation's date: 2013
    Presentation of work at congresses

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  • Experimental tests and numerical modeling to indentify the asymptotic shear-compression mode IIA of concrete fracture

     Montenegro, Oscar Ivan; Sfer, Domingo; Lopez Garello, Carlos Maria; Carol Vilarasau, Ignacio
    Fracture Mechanics of Concrete Structures
    p. 271-277
    Presentation's date: 2013-03
    Presentation of work at congresses

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  • Analysis of mixed-mode fracture in concrete using interface elements and a cohesive crack model

     García Álvarez, V.O.; Gettu, Ravindra; Carol Vilarasau, Ignacio
    Sadhana:academy proceedings in engineering sciences
    Vol. 37, num. 1, p. 187-205
    DOI: 10.1007/s12046-012-0076-2
    Date of publication: 2012-02
    Journal article

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  • Mesomechanical study of high-temperature cracking in mortar and concrete specimens using fracture-based zerothickness interfaces

     Lopez Garello, Carlos Maria; Carol Vilarasau, Ignacio; Rodriguez, Mariana
    International Conference Numerical Modeling Strategies for Sustainable Concrete Structures
    p. 1-9
    Presentation's date: 2012-06
    Presentation of work at congresses

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  • Numerical modeling of micro-indentation tests in Portland cemente paste, using finite elelments with fracture-based zero-thickness interfaces

     Liaudat, Joaquin; Garolera Vinent, Daniel; Lopez Garello, Carlos Maria; Carol Vilarasau, Ignacio
    International Conference on Microstructure Related Durability of Cementitious Composites
    p. 1-6
    Presentation's date: 2012-04
    Presentation of work at congresses

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  • Modeling of drying shrinkage of concrete specimens at the meso-level

     Idiart, Andrés E.; Lopez Garello, Carlos Maria; Carol Vilarasau, Ignacio
    Materials and structures
    Vol. 44, num. 2, p. 1-21
    DOI: 10.1617/s11527-010-9636-2
    Date of publication: 2011-03
    Journal article

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    In this paper, an existing mesomechanical model for cementitious materials is extended to the domain of diffusion-driven phenomena. The model is based on the Finite Element Method, and uses zerothickness interface elements equipped with a fracturebased constitutive formulation to represent cracks. The new developments presented in this paper consist of the application of the model to the hygro-mechanical coupled analysis of drying shrinkage in concrete specimens, explicitly taking into account the influence of (micro) cracks on the diffusion of moisture. In a first part of the paper, the model is presented in some detail, especially the new aspects regarding moisture diffusion including effects of cracks, and H-M coupling. The model predictions are then quantitatively compared with classical drying shrinkage experiments on concrete specimens. The consideration of different assumptions for the relation linking shrinkage strains and weight losses is discussed in some detail. Finally, the effect of size and volume fraction of the main heterogeneities of concrete on the drying process and drying-induced microcracking is also addressed.

  • Chemo-mechanical analysis of concrete cracking and degradation due to external sulfate attack: A meso-scale model

     Idiart, A.; Lopez Garello, Carlos Maria; Carol Vilarasau, Ignacio
    Cement & concrete composites
    Vol. 33, num. 3, p. 411-423
    DOI: 10.1016/j.cemconcomp.2010.12.001
    Date of publication: 2011
    Journal article

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  • An analysis of the design and assembly of the AAR tri-axial machine

     Stokes, Jonathan; Lopez Garello, Carlos Maria; Carol Vilarasau, Ignacio
    Date: 2011-06
    Report

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  • Informe Beca FI

     Carol Vilarasau, Ignacio
    Date: 2011
    Report

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  • Informe final beca FPI

     Carol Vilarasau, Ignacio
    Date: 2011
    Report

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  • Cracking and fracture of concrete at meso-level using zero-thickness interface elements

     Carol Vilarasau, Ignacio; Idiart, A.; Lopez Garello, Carlos Maria; Caballero, A.
    DOI: 10.1007/978-3-7091-0897-0_3
    Date of publication: 2011
    Book chapter

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  • Meso-mechanical modeling of thermal spalling in concrete using fracture-based zero-thickness interface elements

     Rodríguez, M.; Lopez Garello, Carlos Maria; Carol Vilarasau, Ignacio; Willam, K.
    International RILEM Workshop on Concrete Spalling due to Fire Exposure
    p. 237-244
    Presentation's date: 2011-10
    Presentation of work at congresses

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  • Numerical analysis and safety evaluation of a large arch dam founded on fractured rock, using zero-thickness interface elements and a C-F reduction method

     Aliguer, Ignasi; Carol Vilarasau, Ignacio; Alonso Pérez de Agreda, Eduardo; Rio, F.; Griñó, R
    Benchmark Workshop on Numerical Analysis of Dams
    p. 1-7
    Presentation's date: 2011
    Presentation of work at congresses

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  • Numerical analysis and safety evaluation of a large arch dam founded on fractured rock, using zero-thickness interface elements and a c- ø reduction method

     Aliguer, Ignasi; Carol Vilarasau, Ignacio; Alonso Pérez de Agreda, Eduardo
    International Conference on Computational Plasticity Fundamentals and Applications
    p. 1-11
    Presentation's date: 2011
    Presentation of work at congresses

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  • Meso-mechanical analysis of thermal mismatch effects in mortar and concrete specimens using fracture-based zero-thickness interface elements

     Rodríguez, M.; Lopez Garello, Carlos Maria; Carol Vilarasau, Ignacio; Willam, K.
    International Conference on Computational Modeling of Fracture and Failure of Materials and Structures
    p. 1
    Presentation's date: 2011
    Presentation of work at congresses

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  • High temperature effects in mortar and concrete specimens using a meso-mechanical model with fracture based zero-thickness interface elements

     Lopez Garello, Carlos Maria; Carol Vilarasau, Ignacio; Murcia Vela, Juan; Rodriguez, Mariana
    International Conference on Computational Plasticity Fundamentals and Applications
    p. 1-11
    Presentation's date: 2011
    Presentation of work at congresses

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  • Numerical analysis and safety evaluation of a large arch dam founded on fractured rock, using zero-thickness interface elements and a c-fi reduction method

     Aliguer Piferrer, Ignasi; Carol Vilarasau, Ignacio; Alonso Pérez de Agreda, Eduardo
    International Conference on Computational Plasticity Fundamentals and Applications
    p. 1244-1254
    Presentation's date: 2011
    Presentation of work at congresses

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  • Micromechanical analysis of damage and fracture in sandstone rock specimens, using zero-thickness interface elements

     Garolera, Daniel; Carol Vilarasau, Ignacio; Lopez Garello, Carlos Maria
    International Conference on Computational Plasticity Fundamentals and Applications
    p. 1-11
    Presentation's date: 2011
    Presentation of work at congresses

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  • Numerical modelling of pressurized fracture evolution in concrete using zero-thickness interface elements

     Segura, J.M; Carol Vilarasau, Ignacio
    Engineering fracture mechanics
    Vol. 77, num. 9, p. 1386-1399
    DOI: 10.1016/j.engfracmech.2010.03.014
    Date of publication: 2010-06
    Journal article

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  • Análisis del hormigón en modo mixto de fractura utilizando un modelo meso-estructural con elementos junta.

     Lopez Garello, Carlos Maria; Carol Vilarasau, Ignacio; Rodriguez, Mariana
    Anales de mecánica de la fractura
    Vol. I, num. 27, p. 247-252
    Date of publication: 2010
    Journal article

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    En este trabajo se presentan resultados de la simulación numérica de algunos ensayos experimentales sobre muestras de hormigón sometidas a carga biaxial que combina tracción y corte [1]. Para ello se emplea una modelización en la que se representan explícitamente los principales componentes de la estructura interna del hormigón a nivel mesoescala. Los ensayos experimentales se realizaron mayoritariamente en muestras de 200 mm de lado, si bien en algunos casos de carga también se emplearon muestras de 100 y 50 mm. En un trabajo anterior presentado en el Congreso del Grupo Español de Fractura del año 2009 se ha estudiado una muestra de 200 mm con tamaño máximo de árido de 16 mm. En este artículo se analiza ahora la muestra de 50 mm de lado con un tamaño máximo de árido similar al de las probetas empleadas en los experimentos (2mm). Los resultados obtenidos en uno de los estados de carga han permitido reproducir satisfactoriamente el comportamiento carga-desplazamiento (tensión-desplazamiento), así como la formación y evolución de la tendencia de fisuración detectada en los ensayos llevados a cabo en [1] y similares en [2].-----------------------------------------ABSTRACT This paper presents the results of the numerical simulation of some of the experimental tests on concrete samples subjected to different biaxial loading paths combining tension and shear [1]. The study uses a meso-structural model which explicitly represents the main components of the internal structure of concrete at meso-scale level. The experimental tests were conducted mostly in samples of 200 mm side, although in some load cases were also used samples of 100 and 50mm side. In a previous work presented in the Congress of the Spanish Group of Fracture (2009) a sample of 200 mm side with maximum aggregate size 16mm has been studied. This paper now examines the sample of 50 mm side with a maximum aggregate size similar to the used in the experimental test (2mm). The numerical results obtained in one of the loading conditions have allowed satisfactorily reproduce the load-displacement behaviour (tension-displacements) and the cracking patterns detected in the experimental tests conducted in [1] and similarly in [2].

  • NUEVOS DESARROLLOS Y APLICACIONES DEL ANALISIS MULTIESCALA ACOPLADO THMC A PROBLEMAS DE DETERIORO EN

     Lopez Garello, Carlos Maria; Garolera Vinent, Daniel; Carol Vilarasau, Ignacio
    Competitive project

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  • Recent developments in mesomechanical analysis of quasibrittle materials using interface elements

     Carol Vilarasau, Ignacio; Lopez Garello, Carlos Maria; Idiart, A.; Rodríguez, M.; Garolera, Daniel
    Engineering Mechanics Institute Conference
    p. 76
    Presentation's date: 2010
    Presentation of work at congresses

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  • Análisis del hormigón en modo mixto de fractura utilizando un modelo meso-estructural con elementos junta.

     Lopez Garello, Carlos Maria; Carol Vilarasau, Ignacio; Rodriguez, Mariana
    Encuentro del Grupo Español de Fractura
    p. 247-252
    Presentation of work at congresses

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    En este trabajo se presentan resultados de la simulación numérica de algunos ensayos experimentales sobre muestras de hormigón sometidas a carga biaxial que combina tracción y corte [1]. Para ello se emplea una modelización en la que se representan explícitamente los principales componentes de la estructura interna del hormigón a nivel mesoescala. Los ensayos experimentales se realizaron mayoritariamente en muestras de 200 mm de lado, si bien en algunos casos de carga también se emplearon muestras de 100 y 50 mm. En un trabajo anterior presentado en el Congreso del Grupo Español de Fractura del año 2009 se ha estudiado una muestra de 200 mm con tamaño máximo de árido de 16 mm. En este artículo se analiza ahora la muestra de 50 mm de lado con un tamaño máximo de árido similar al de las probetas empleadas en los experimentos (2mm). Los resultados obtenidos en uno de los estados de carga han permitido reproducir satisfactoriamente el comportamiento carga-desplazamiento (tensión-desplazamiento), así como la formación y evolución de la tendencia de fisuración detectada en los ensayos llevados a cabo en [1] y similares en [2].-----------------------------------------ABSTRACT This paper presents the results of the numerical simulation of some of the experimental tests on concrete samples subjected to different biaxial loading paths combining tension and shear [1]. The study uses a meso-structural model which explicitly represents the main components of the internal structure of concrete at meso-scale level. The experimental tests were conducted mostly in samples of 200 mm side, although in some load cases were also used samples of 100 and 50mm side. In a previous work presented in the Congress of the Spanish Group of Fracture (2009) a sample of 200 mm side with maximum aggregate size 16mm has been studied. This paper now examines the sample of 50 mm side with a maximum aggregate size similar to the used in the experimental test (2mm). The numerical results obtained in one of the loading conditions have allowed satisfactorily reproduce the load-displacement behaviour (tension-displacements) and the cracking patterns detected in the experimental tests conducted in [1] and similarly in [2].

  • Modeling the chemo-mechanical behavior of concrete at the meso-scale: application to external sulfate attack

     Idiart, A.; Carol Vilarasau, Ignacio; Lopez Garello, Carlos Maria
    European Conference on Computational Mechanics
    p. 1-2
    Presentation's date: 2010
    Presentation of work at congresses

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  • Hygro-mechanical model for concrete specimens at the meso-level: application to drying shrinkage

     Idiart, Andrés E.; Lopez Garello, Carlos Maria; Carol Vilarasau, Ignacio
    Computational Modelling of Concrete and Concrete Structures
    p. 487-495
    Presentation's date: 2010-03
    Presentation of work at congresses

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  • Análisis meso-estructural de la fractura del hormigón en modo mixto

     Lopez Garello, Carlos Maria; Carol Vilarasau, Ignacio; Rodriguez, Mariana
    Anales de mecánica de la fractura
    Vol. 26, num. 2, p. 452-457
    Date of publication: 2009
    Journal article

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  • Análisis numérico mesomecánico del ataque sulfático externo en hormigón

     Idiart, Andrés; Carol Vilarasau, Ignacio; Lopez Garello, Carlos Maria
    Anales de mecánica de la fractura
    Vol. 26, num. 2, p. 458-463
    Date of publication: 2009
    Journal article

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  • Análisis numérico meso-estructural del hormigón en modo mixto de fractura

     Lopez Garello, Carlos Maria; Carol Vilarasau, Ignacio; Rodriguez, Mariana
    Mecánica computacional
    Vol. 28, p. 1027-1041
    Date of publication: 2009
    Journal article

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  • GT-051 Modelling of drying shrinkage of concrete specimens at the meso-level

     Idiart, A; Lopez Garello, Carlos Maria; Carol Vilarasau, Ignacio
    Date: 2009-09
    Report

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  • Nuevos desarrollos y aplicaciones del análisis multiescala acoplado THMC a problemas de deterioro en hormigón

     Pardo Trafach, Patricia Teresa; Carol Vilarasau, Ignacio; Lopez Garello, Carlos Maria
    Competitive project

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  • Coupled analysis of degradation processes in concrete specimens at the meso-level  Open access

     Idiart Castellano, Andrés Enrique
    Department of Geotechnical Engineering and Geo-Sciences, Universitat Politècnica de Catalunya
    Theses

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    En los últimos años, el análisis numérico de problemas acoplados, como los procesos de degradación de materiales y estructuras relacionados con los efectos medioambientales, ha cobrado especial importancia en la comunidad científica de la mecánica del hormigón. Problemas de este tipo son por ejemplo el ataque químico, el efecto de altas temperaturas o la retracción por secado.Tradicionalmente, los análisis acoplados existentes en la literatura se han realizado a nivel macroscópico, considerando el material como un medio continuo y homogéneo. Sin embargo, es bien conocido que el origen de la degradación observada a nivel macroscópico, a menudo es debida a la interacción entre los áridos y el mortero, sobre todo cuando se dan cambios de volumen diferenciales entre los dos componentes. Esta es la razón por la que el análisis mesomecánico está emergiendo como una herramienta potente para estudios de materiales heterogéneos, aunque actualmente existen escasos modelos numéricos capaces de simular un problema acoplado a esta escala de observación.En esta tesis, la aplicabilidad del modelo meso-mecánico de elementos finitos, desarrollado en el seno del grupo de investigación durante los últimos quince años, se extiende al análisis de problemas acoplados higro-mecánicos y químico-mecánicos, con el fin de estudiar la retracción por secado y el ataque sulfático externo en muestras de hormigón. La generación numérica de mesogeometrías y mallas de elementos finitos con los áridos de mayor tamaño rodeados de la fase mortero se consigue mediante la teoría de Voronoï/Delaunay Adicionalmente, con el fin de simular las principales trayectorias de fisuración, se insertan a priori elementos junta de espesor nulo, equipados con una ley constitutiva basada en la mecánica de fractura no lineal, a lo largo de todos los contactos entre árido y matriz, y también en algunas líneas matriz-matriz.La aportación principal de esta tesis es, conjuntamente con la realización de análisis acoplados sobre una representación mesoestructural del material, la simulación no solo de la formación y propagación de fisuras, sino también la consideración explícita de la influencia de éstas en el proceso de difusión.Los cálculos numéricos se realizan mediante el uso de los códigos de elementos finitos DRAC y DRACFLOW, previamente desarrollados en el seno del grupo de investigación, y acoplados mediante una estrategia staggered. Las simula-ciones realizadas abarcan, entre otros aspectos, la evaluación del compor-tamiento acoplado, el ajuste de parámetros del modelo con resultados experimentales disponibles en la bibliografía, diferentes estudios del efecto de los áridos en la microfisuración inducida por el secado y las expansiones debidas al ataque sulfático, así como el efecto simultáneo de los procesos gobernados por difusión y cargas de origen mecánico. Los resultados obtenidos concuerdan con observaciones experimentales de la fisuración, el fenómeno de spalling y la evolución de las deformaciones, y muestran la capacidad del modelo para ser utilizado en el estudio de problemas acoplados en los que la naturaleza heterogénea y cuasi-frágil del material tiene un papel predominante.

  • Computational modeling of external sulfate attack in concrete at the meso-level

     Idiart, Andrés; Carol Vilarasau, Ignacio; Lopez Garello, Carlos Maria; Murcia, Juan
    International Conference on Computational Plasticity Fundamentals and Applications
    p. 1-4
    Presentation's date: 2009-09
    Presentation of work at congresses

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  • Meso-mechanical analysis of the fracture of concrete specimens in mixed mode

     Rodrígez, Mariana; Lopez Garello, Carlos Maria; Carol Vilarasau, Ignacio; Caner, Ferhun Cem
    International Conference on Computational Plasticity Fundamentals and Applications
    p. 1-4
    Presentation's date: 2009-09
    Presentation of work at congresses

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    This paper describes recent numerical simulation results of some experiments carried out by Nooru-Mohamed to study mixed mode fracture of concrete. The numerical simulation is based on a meso-mechanical model developed in the group of Mechanics of Materials UPC, which represents the largest aggregate particles explicitly, and represent cracks in a discrete manner by inserting zero-tickness interface elements in all potential crack trajectories a priori of the analysis.

  • Viscoplastic multilaminate model for jointed rock with stress-prescribed using a "stress-prescribed" LEGI scheme

     Caballero Jurado, Antonio; Garolera, Daniel; Carol Vilarasau, Ignacio; Gens Sole, Antonio
    International Conference on Rock Joints and Jointed Rock Masses
    p. 1-8
    Presentation's date: 2009-01
    Presentation of work at congresses

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